Method of bending metal



April 21, 1925. 1,534,314

... l. HEINTZ METHOD OF BENDING METAL Filed April '50, 1923 3 Sheets-Sheet 1 y 172g' .z

ATTORNEY ,Api-1t zr, *m2-s. 1534314 L. l. HElNTz METHOD OF BENDING METAL Filed April 30, 1923 5 Sheets-Sheet 2 fig.

IN VEN TOR ATTORNEY L. l. HEINTZ METHOD OF BENDING METAL Apil 2l, 1925.

FiledyApril 30,V 1923 I5 Sheets-Sheet 5 if 11,111,171, I

nl... ...'11 n IN V EN TOR A TTORNE Y Patented Apr. 2l, 1925.

UNITED STATES PATENT OFFICE.

LEO I. HEIN'I'Z, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR TO HEINTZ MANU- FACTURING COMPANY, F PHILADELPHIA, PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA.

METHOD OF EENIDING METAL.

Application led April 30, 1923.

To all whom z't may concern:

Be it known that I, Lne I. HEINTZ, a citizen of the United States, residing at Philadelphia, in the county ot Philadelphia 5 and State of Pennsylvania, have invented certain new and useful Improvements in a Method of Bending Metal, ot which the following is a specification.

This invention relates to metal working,

and more particularly to a method of producing from sheet metal hollow articles which have longitudinal curvature and which are entirely or approximately closed in cross-section.

In my Patent No. 1,525,936, dated Feb. 10, 1925, I have disclosed and claimed articles of manufacture which are particularly well adapted for use as sills in vehicle body frames and which are constructed of a single integral piece of sheet metal shaped so as to be closed and hollow in cross-section and to be longitudinally curved, thus torming in e'liect a closed box lgirder having desired longitudinal curvature. I-Ieretofore articles of similar construction have been constructed by shaping a plurality of separate pieces of sheet metal and then securing such pieces together by bolting or welding. It is my aim to provide a method ot producing articles of the character referred to from a single integral piece of sheet metal. Another object of my invention is to provide a method whereby articles having hollow and closed cross-section and longitudinal curvature may be produced Jfrom a single piece of sheet metal quickly, economically and accurately and to the shape and size desired. Another obiect of this invention is to provide a method whereby a sheet metal article having a hollow and closed cross-section may be curved longitudinally without cracking or otherwise damaging the article, and without altering its crosssectional contour. A further object ot this invention is to provide apparatus and appliances adapted for use in connection with the practice of the method above described. Other obiects will be in part obvious and in part pointed out hereinafter.

In accordance with my invention, I tirst Serial No. 635,478.

shape a single integral piece of sheet metal olf suitable length and width transversely into the final cross-sectional shape desired by bending the sheet about a straight core or form which is shaped to give the sheet such cross-sectional contour. The core, however, is flexible, and I then bend the core or mandrel form, together with the closely enveloping shaped sheet metal, longitudinally to give the shaped sheet of metal the longitudinal curvature desired in the final article. which is now finally and completely formed. As a linal operation I draw the flexible mandrel lengthwise out of an open end of the enveloping shaped article without altering either its cross-sectional or longitudinal shape. The simplicity of the method is selfeevident, and results in the production et an article consisting of a single integral piece of sheet metal and which has heretoihre consisted ot a plurality ot sheet metal pieces joined together.

In order that a clearer understanding of my invention may be had. attention is hereby directed to the accompanying' drawings` forming a part of this application and illustratinof one possible embodiment ot mv invention. For purposes of illustration I have chosen to describel specifically and to illustrate one manner of practicing my ins vention for the production ot sidesills for vehicle body trames. such sills being described and illustrated in mv said patent. Referring to the drawinrrs. Figure 1 is a pian view ot a sheet metal blank trom which a sill member is to be constructed: Fili'. 2 is a perspective view ot said sheet atter it has been subiected to a preliminary transverse hendino: or shapinfr operation: Firr. 3 is a side view of a mandrel or core inserted into the sheet so shaped? Fior. 4 is a side view ot the sheet hout transversely about the mandrel and into lits final closed crosssectional shape: Fie. 5 is a .side view ot the sill bent loneitudinally to the final shape desired. the mandrel still heine enclosed bv `said sheet and heut to the same curvaturef Fig. 6 is a side view oi the .sheet "t metal in the shape shown in Fig. 5 except that the mandrel nas been removed; Fig. 7 includes.y

is separate side' and end views, a pair of die members adapted to be used to give the desired longitudinal curvature to the sheet metal sill while the mandrel i:` contained therein; Fig. 8 includes, in separate front, side and top views, a central unit of the mandrel or core; F ig. 9 includes, in separate front, side and top views, an end member of said mandrel or core; Figs. l() and ll are sectional views of the completed sill, and are taken respectively on lines 10- 1() and 11-11 of Fig. 6; Fig. 'l2 is a top view of a modified form of sill which may be produced by the method of my invention; and Fig. 13 is a side view of said modified sill. Similar reference characters refer to similar parts throughout the several views of the drawings.

Referring to the drawings, in Figs. G, l0, ll, 12, and 13 I have shown metallic frame members suitable for use in vehicle body frames, which frame members may be constructed by following the method of my invention. Two modifications of such frame members are shown, differing from each other only in that the frame member l illustrated in Fig. 6 is curved longitudinally in one plane only, as at 2, while in the other modification the frame member 3 has longitudinal curvature in two different planes, as at 4 and 5. From end to end these fran'ie members are of hollow. closed, transverse cross-section, each forming in effect a box girder consisting of a single integral piece of sheet metal. lf desired, these frame members may be constructed with horizontal juxtaposed flanges 6 along the longitudinal edges ofthe shaped piece of sheet metal, and these flanges may be secured together by welding or by other suitable means.

The principal feature of novelty of my invention is the production of such frame members from a single integral piece of sheet metal. ln carrying outl the method l provide a blank 7 of sheet metal of suitable shape and size, and by a suitable stamping or bending operation bend this blank transversely into channel shaped form, as at 8, Fig. 9. I now provide a device which is inserted into the channel of the channel shaped piece 8, and which serves as a form about which the sheet S may be bent transversely. I now bend the sheet metal about this device 9 by a suitable stamping or bending operation to form the sheet metal into the hollow, substantially closed, transverse cross-sectional shape which is desired in the filial article. The flanges 6 may be bent up and brought together during this operation.

The device 9 above referred to has thi` same transverse peripheral shape as the interior transverse shape desired in the final artic-le; and when the piece of sheet metal has been transversely formed to shape about this device 9, serving as a form, the device 9 will completely fill the hollow in the member and re nforce the same during the next operation, which gives longitudinal curvature to the member.

To permit longitudinal curvature to be given to the sheet metal member while the device 9 is enclosed therein, the device 9 is so constructed that it is flexible. To this end the device 9 is constructed of a plurality7 of rigid units l0 which are strung together by means of flexible material, such as flexible wires l1, which extend through perforations in the various units. The sheet metal member of final cross-sectional shape, together with the flexible device 9 enclosed therein, is seated in a suitable die l2 which is adapted to close thereupon and bends the shaped sheet metal together with the enclosed device 9, to give the desired longitudinal. curvature to the sheet metal. During` this operation the device 9 acts as a reenforcing mandrel for the sheet metal and serves to maintain the transverse cross-sectional shape previously given thereto. The frame member` of the desired cross-sectional and longitudinal. shape corresponding to the form shown in Fig. G has now been produced, and the final step consists in withdrawing the flexible mandrel 9 out of an open end of the completely formed member without altering either the cross-sectional shape or the longitudinal curvature of this member. Since the mandrel 9 is flexible, this may be accomplished readily by a pulling` operation.

To provide a frame member having longitudinal curvature in two planes, after the member with the mandrel 9 enclosed therein has been given longitudinal curvature in one direction, as by means of dies l2. it is bent in the other desired plane by a similar step involving the use of the same or another set of dies. In this manner the member may be given longitudinal curvature in as manyv directions as is desired, the n'zandrel 9 not being removed from the member until all such bending operations have been completed.

Obviously the method of this invention is not limited to use for the production of frame members for vehicle bodies. but may be employed as well for the production of articles adapted for other uses.

As many changes could be made in the above construction and as many apparently widely different embodiments of this invention could be made without departing from the scope thereof, it is intended that all mat ter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

llVhat claim is A method of the character described` which consists of bending a piece of sheet metal transversely about a flexible mandrel comprising flexibly connected rigid units to give said sheet a substantially closed, hollow, cross-sectional shape, and bendinsaid shaped Sheet and mandrel longitudinally to give Said shaped sheet longitudinal curvw ture Without altering its Said hollow cross- Sectional Shape, nd withdrawing said mandrel from said sheet so shaped Without altering either its cross-sectional shape or its longitudinal curvature.

This specification signed this 27th day of April, 1923.

LEO I. HEINTZ. 

